Britain's Adam Gemili says he "does not know" if he will make the World Championships in Beijing after a hamstring injury.
Earlier in June the 21-year-old became the first ever Briton to run both the 100m and 200m in under 10 seconds and in less than 20 seconds respectively.
But just after registering 9.97 seconds in the 100m at the Birmingham Grand Prix, he fell, injuring his right leg.
"I'm slowly but surely recovering," said the European 200m champion.
"I'm not trying to rush things, but if I can get back on the track before the end of the season that is great."
The World Championships run from 22-30 August at the Beijing National Stadium, where the 2008 Olympics were held.
"Of course it would be great if I was able to make Beijing, but I do not know if that will be possible yet and I am not going to risk anything," added Gemili.
"We have to look at the bigger picture, with the Rio Olympics obviously the main priority."